package com.terren.spider.util.common;

import java.math.BigDecimal;

import org.apache.commons.lang.RandomStringUtils;
import org.apache.commons.lang3.math.NumberUtils;
 
public class NumberUtil {
 
	private static final int DEF_DIV_SCALE = 2;
	
	/**
	 * 判断字符串是否为数字
	 * @param num
	 * @return
	 */
	public static boolean isNumber(String num){
		return NumberUtils.isNumber(num);
	}
	
	public static Double createDouble(String num) {
		if (isNumber(num)) {
			return NumberUtils.createDouble(num);
		}
		return 0.0;
	}
	
	
	/**
	 * @return 返回12位随机数
	 */
	public static String randomNumber()
	{
		return RandomStringUtils.randomNumeric(12);
	}
	/**
	 * @param parm
	 * @return 返回指定位数随机数
	 */
	public static String randomNumber(int parm)
	{
		return RandomStringUtils.randomNumeric(parm);
	}
    /**
 
	/**
	 * * 两个Double数相加 *
	 * 
	 * @param v1 *
	 * @param v2 *
	 * @return Double
	 */
	public static Double add(Double v1, Double v2) {
		BigDecimal b1 = new BigDecimal(v1.toString());
		BigDecimal b2 = new BigDecimal(v2.toString());
		return new Double(b1.add(b2).doubleValue());
	}
 
	/**
	 * * 两个Double数相减 *
	 * 
	 * @param v1 *
	 * @param v2 *
	 * @return Double
	 */
	public static Double sub(Double v1, Double v2) {
		BigDecimal b1 = new BigDecimal(v1.toString());
		BigDecimal b2 = new BigDecimal(v2.toString());
		return new Double(b1.subtract(b2).doubleValue());
	}
 
	/**
	 * * 两个Double数相乘 *
	 * 
	 * @param v1 *
	 * @param v2 *
	 * @return Double
	 */
	public static Double mul(Double v1, Double v2) {
		BigDecimal b1 = new BigDecimal(v1.toString());
		BigDecimal b2 = new BigDecimal(v2.toString());
		return new Double(b1.multiply(b2).doubleValue());
	}
 
	/**
	 * * 两个Double数相除 *
	 * 
	 * @param v1 *
	 * @param v2 *
	 * @return Double
	 */
	public static Double div(Double v1, Double v2) {
		BigDecimal b1 = new BigDecimal(v1.toString());
		BigDecimal b2 = new BigDecimal(v2.toString());
		return new Double(b1
				.divide(b2, DEF_DIV_SCALE, BigDecimal.ROUND_HALF_UP)
				.doubleValue());
	}
 
	/**
	 * * 两个Double数相除，并保留scale位小数 *
	 * 
	 * @param v1 *
	 * @param v2 *
	 * @param scale *
	 * @return Double
	 */
	public static Double div(Double v1, Double v2, int scale) {
		if (scale < 0) {
			throw new IllegalArgumentException(
					"The scale must be a positive integer or zero");
		}
		BigDecimal b1 = new BigDecimal(v1.toString());
		BigDecimal b2 = new BigDecimal(v2.toString());
		return new Double(b1.divide(b2, scale, BigDecimal.ROUND_HALF_UP)
				.doubleValue());
	}
	
	/**
	 * @param v1
	 * @return 返回指定Double的负数
	 */
	public static Double neg(Double v1) {
		return sub(new Double(0),v1);
	}
	
}
